diff mbox series

[1/1] sched/psi: avoid resetting the min update period when it is unnecessary

Message ID 20230514163338.834345-1-surenb@google.com
State New
Headers
Series [1/1] sched/psi: avoid resetting the min update period when it is unnecessary |

Commit Message

Suren Baghdasaryan May 14, 2023, 4:33 p.m. UTC 
  From: Yang Yang <yang.yang29@zte.com.cn>

Psi_group's poll_min_period is determined by the minimum window size of
psi_trigger when creating new triggers. While destroying a psi_trigger,
there is no need to reset poll_min_period if the psi_trigger being
destroyed did not have the minimum window size, since in this condition
poll_min_period will remain the same as before.

Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Acked-by: Suren Baghdasaryan <surenb@google.com>
---
rebase of https://lore.kernel.org/all/202305121642367753446@zte.com.cn/
over git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core branch

 kernel/sched/psi.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

Comments

Peter Zijlstra May 15, 2023, 8:27 a.m. UTC | #1 
On Sun, May 14, 2023 at 09:33:38AM -0700, Suren Baghdasaryan wrote:
> From: Yang Yang <yang.yang29@zte.com.cn>
> 
> Psi_group's poll_min_period is determined by the minimum window size of
> psi_trigger when creating new triggers. While destroying a psi_trigger,
> there is no need to reset poll_min_period if the psi_trigger being
> destroyed did not have the minimum window size, since in this condition
> poll_min_period will remain the same as before.
> 
> Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
> Acked-by: Suren Baghdasaryan <surenb@google.com>
> ---
> rebase of https://lore.kernel.org/all/202305121642367753446@zte.com.cn/
> over git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched/core branch

Thanks!
diff mbox series

Patch

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index b49af594ad28..81fca77397f6 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1407,11 +1407,16 @@  void psi_trigger_destroy(struct psi_trigger *t)
 			group->rtpoll_nr_triggers[t->state]--;
 			if (!group->rtpoll_nr_triggers[t->state])
 				group->rtpoll_states &= ~(1 << t->state);
-			/* reset min update period for the remaining triggers */
-			list_for_each_entry(tmp, &group->rtpoll_triggers, node)
-				period = min(period, div_u64(tmp->win.size,
-						UPDATES_PER_WINDOW));
-			group->rtpoll_min_period = period;
+			/*
+			 * Reset min update period for the remaining triggers
+			 * iff the destroying trigger had the min window size.
+			 */
+			if (group->rtpoll_min_period == div_u64(t->win.size, UPDATES_PER_WINDOW)) {
+				list_for_each_entry(tmp, &group->rtpoll_triggers, node)
+					period = min(period, div_u64(tmp->win.size,
+							UPDATES_PER_WINDOW));
+				group->rtpoll_min_period = period;
+			}
 			/* Destroy rtpoll_task when the last trigger is destroyed */
 			if (group->rtpoll_states == 0) {
 				group->rtpoll_until = 0;